CVE-2026-98856
Received Received - Intake

kprobes: Fix optkprobe overlap handling in Linux kernel

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: kprobes: Skip disarmed probes when checking optkprobe overlap On x86, an optkprobe at A replaces five bytes with a jump. If a disabled probe B is at A+2, get_optimized_kprobe() stops at B when arming a new probe C at A+4. It leaves A optimized: A A+1 A+2 A+3 A+4 A's jump | e9 | d0 | d1 | d2 | d3 | after C | e9 | d0 | d1 | d2 | cc | The INT3 for C overwrites the last byte of A's jump displacement, so execution can jump to the wrong address. B can have prepared optinsns while disarmed, but has no jump to unoptimize. Continue past disarmed and unprepared probes to find the active optimized probe before arming a probe in its jump.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98856
EUVD
EUVD-2026-103796

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
Linux Linux afd66255b9a48f5851326ddae50e2203fbf71dc9
Linux Linux afd66255b9a48f5851326ddae50e2203fbf71dc9
Linux Linux afd66255b9a48f5851326ddae50e2203fbf71dc9
Linux Linux afd66255b9a48f5851326ddae50e2203fbf71dc9
Linux Linux 2.6.34

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves kprobes, a debugging mechanism. When an optkprobe (optimized kprobe) is placed at address A, it replaces five bytes with a jump instruction. If another disabled probe B is located at A+2, the system may incorrectly identify B as the active probe when arming a new probe C at A+4. This leaves the original probe A in an optimized state with incorrect jump instructions, potentially causing execution to jump to the wrong address.

Impact Analysis

This vulnerability could lead to arbitrary code execution or system crashes if exploited. Attackers might manipulate probe placements to redirect execution flow, causing unintended behavior or privilege escalation. Systems relying on kprobes for debugging or security monitoring could be compromised.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the kprobes vulnerability. Monitor kernel logs for probe-related errors or crashes that may indicate exploitation attempts.

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